System creates multilayer PET preforms

Designed to create parts for a specific carbonated soft drink application, a new 72-cavity PET coinjection system has been developed. Using a multilayer PET production design, the system boosted production 50 percent compared to the previous 48-cavity system, and it reportedly has more than 20 percent higher output-to-capital ratio. In addition, the 72-cavity system is compatible with the same machine platform as the 48-cavity unit, so no additional floor space is needed.

Called the Kortec Pro Series GL300/72, the system uses a coinjection hot runner system and nozzles along with a multimaterial Husky GL300 press and 72-cavity mold. Designed to accommodate Husky?s micropitch mold technology, the new nozzles for this project allow preforms to be spaced 50 mm apart. A larger reciprocating screw barrier injection unit and a two-stage PET injection unit are used to shoot the preforms.

A centralized control is closed loop, and the dual injection units send material to two separate, balanced manifold systems. This reportedly creates optimized and independent material temperature as well as overall process control.

The system was created for a 250-ml PET bottle that needed more than 16 weeks of shelf life?twice that of a monolayer bottle. Designed to have the look and feel of glass, the preform is thick, weighing in at 28.8g with a stepped core and champagne-bottle-style base. The barrier material is nylon and constitutes 3.5 percent of the bottle by weight. The nylon is sandwiched in the preform between the inner and outer PET layers. The multilayer container is said to have two times the barrier performance of its monolayer equivalent. The cycle time is less than 18 seconds, and over the course of 8000 production hours, the system will reportedly make 115 million preforms.

Kortec Inc., Beverly, MA
(978) 921-4300; www.kortec.com

Husky Injection Molding Systems
Bolton, ON
(905) 951-5000; www.husky.ca